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Unit Converter
Convert common length units with a clean result-first layout, quick pairs, and formula-based results that update instantly.
Public suite
Simple useful apps, reintroduced one route at a time.
UsefulToday is being rebuilt as a quiet collection of practical tools that are easy to understand and easy to trust. The live tools are below.
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Currency Converter
Convert between major currencies using current exchange rates, with a clean mobile layout and cached fallback when the latest request is unavailable.
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Compound Interest Calculator
See how money grows over time with compound interest and regular contributions. Includes a growth chart, yearly breakdown, and quick scenario presets.
🏀 New
March Madness Bracket Picker
Generate an optimal 2026 bracket using 40 years of historical upset data. Four strategy modes, manual overrides, and full export.
✨ New
Thermastyle
What should you wear this week? Enter your city, get a 7-day forecast, and see outfit recommendations for every day — with a reactive clothes-rack mascot.